/*
 *  Copyright 2008-2010 NVIDIA Corporation
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */


/*! \file adjacent_difference.h
 *  \brief Host implementation of adjacent_difference.
 */

#pragma once

#include <thrust/iterator/iterator_traits.h>

namespace thrust
{
namespace detail
{
namespace host
{

template <class InputIterator, class OutputIterator, class BinaryFunction>
OutputIterator adjacent_difference(InputIterator first, InputIterator last,
                                   OutputIterator result,
                                   BinaryFunction binary_op)
{
    typedef typename thrust::iterator_traits<InputIterator>::value_type InputType;

    if (first == last)
        return result;

    InputType curr = *first;

    *result = curr;

    while (++first != last)
    {
        InputType next = *first;
        *++result = binary_op(next, curr);
        curr = next;
    }

    return ++result;
}

} // end namespace host
} // end namespace detail
} // end namespace thrust

